To construct a block for motion compensation suitable when image information in an RGB color space is encoded with an encoding method including motion compensation.

The image encoder and the image encoding method comprise processes of: conducting a motion compensation processing by dividing an image into blocks having the predetermined number of pixels for respective components of an R pixel component, a G pixel component, and a B pixel component; conducting a frequency conversion over the processed image data; and then performing entropy encoding on the processed image data to generate code data. Motion compensation means divides a block of a G pixel component in an encoding object frame between even lines and odd lines and conducts motion compensation processing for a pixel sub-block of even lines and for a pixel sub-block of odd lines, respectively.